1. Field of the Invention
The present invention relates to transparent thin-films and, more particularly, to an imaging, differential optical sectioning interference microscopy (DOSIM) system and method for measuring refractive indices n and thicknesses d of transparent thin-films.
2. Description of the Related Art
Refractive indices (n) and thicknesses (d) of thin-films are essential parameters for modern electronic and optoelectronic devices. At present, ellipsometers are the preferred tool for measuring refractive indices and thicknesses of transparent thin-films.1 Such conventional ellipsometers use an obliquely incident light path to illuminate the specimens films. However, the geometry associated with such conventional ellipsometers tends to increase the lateral resolution of the measurement in the order of larger than tens of micrometers.
A variety of imaging ellipsometers have been developed to improve the lateral resolution for thin-film characterizations.2-4 However, the optical geometry of inclined illumination or obliquely illuminated light path still renders the lateral resolution in the order of a few micrometers. Another recent proposed solution for achieving sub-micrometer lateral resolution involved the use of a high-resolution imaging ellipsometer using a high numerical aperture (NA) microscope objective as a probe.5 However, such a proposed solution does not indicate that the simultaneous measurement of n and d of inhomogeneous thin-films can be achieved. In view of the foregoing, it is apparent there is a need for a method and system for measuring refractive indices (n) and thicknesses (d) of transparent thin-films.